- Hi,I have a large gum tree in my backyard of unknown type. At the moment it is blossoming. We have lots of bees lying around in the backyard that are either dead or dying. Do you know what causes this? It happend last August when the tree was flowering also. It concerns me as i have 2 small children and we can't play in the backyard as there are so many bees on the ground. We have already had 2 bee stings. I would be appreciate it if you can help me out.